Research On The Integrated Control Of Electric Vehicle RBS And ABS

The regenerative brake system(RBS)is one of the key technologies of electric vehicles.It recycles the vehicle’s kinetic energy by transforming it into electric energy with motor when the vehicle is braking or slowing down.Anti-locking braking system(ABS)is the most basic active safety control system for automobiles.ABS adjusts brake friction automatically using Machine-Electricity-Hydraulic system,to maintain the wheel unlocked and slip rate around the best slip rate.RBS provides a new energy transform form and new electric-braking method for vehicle braking or slowing down.In this dissertation,theory analysis and experimental research methods are combined.Integrated control strategy of RBS and ABS are carried out.Control theory of SVPWM three phase rectifier braking torque of PMSM motor in electric vehicles,variable hybrid energy storage equipment in serial and parallel structure,road condition recognition and the integrated control strategy of ABS are covered in this dissertation.Those research could be concluded as:1.Operating characteristics of PMSM motor in electric vehicles and its model are analyzed and created.Control strategy of the motor’s braking torque is proposed in the PMSM motor’s d,q synchronous rotating reference coordinate system.According to the characteristics of power,torque and efficiency of PMSM motor,control strategy of the regenerative braking torque based on control strategy of SVPWM three phase rectifier optimal torque and optimal power is proposed as well.Dynamic control of motor braking power and braking torque is implemented only by controlling rectified current value of SVPWM,which realized control of motor brake power flow.2.Characteristics of PMSM motor,super-capacitor and power battery of electric vehicles in braking process are researched.After analyzing problems of bi-energy storage devices employed in traditional electric vehicles,based on bidirectional DC/DC converter,serial and parallel controllable hybrid energy storage structure of lithium-ion battery and super-capacitor are designed and control strategy of energy recycle is proposed.The motor braking torque control model based on the super-capacitor charging current PI negative feedback control is designed.By controlling and measuring parameters of hybrid energy storage devices and bidirectional DC/DC converter,it can recycle regenerate braking energy and control motor braking torque.Based on PMSM motor brake power flow,dynamic distribution strategy of electric vehicle braking torque is proposed,which provides a new resolution for optimization of integrated control of RBS and ABS for electric vehicles.3.By researching control strategy of ABS in electric vehicle,integrated control structure of RBS and ABS of electric vehicle is designed.Mathematical simulation models of in RBS of electric vehicle are created,and strategy of braking torque dynamic distribution of electric vehicle based on PMSM motor braking flow is simulated.Integrated control strategy of RBS and ABS using fuzzy recognition and algorithm of road condition fuzzy recognition of RBS based on the created model with different coefficient of road adhesion and slip rate are proposed.Simulation experiments in different road condition are carried out,which verified the effectiveness of integrated control strategy based on road condition recognition of electric vehicle.In the process of simulation,slip rate of vehicle is maintained around the best slip rate,and efficiency of energy recycling is improved by 14.2%4.Verification algorithm based on road condition recognition for RBS and ABS integrated control strategy is researched.RBS experimental bench which is capable of adjusting different road condition is designed,which includes motor and its control system,hybrid energy storage system,inertia mass simulation system and braking distance simulation system.Different coefficients of road adhesion in RBS are realized by adjusting the magnetizing current in the magnetic powder clutch.RBS experiments are implemented on the bench under different braking intensities and on different roads,and the results show that RBS road recognition algorithm is capable of recognizing coefficients of road adhesion in real time and could implement the strategy of braking torque dynamic distribution in different road conditions.The proposed integrated control strategy of RBS and ABS could improve energy recycling efficient under different road condition and reduce braking time and braking distance.